The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Jan. 28, 2020

Filed:

Nov. 30, 2015
Applicant:

Dynomax Drilling Tools Usa, Inc., Leduc, CA;

Inventors:

David S. Cramer, Okotoks, CA;

Michael J. Harvey, Calgary, CA;

David D. Devlin, Calgary, CA;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
E21B 21/10 (2006.01); E21B 4/02 (2006.01); E21B 34/08 (2006.01); E21B 34/00 (2006.01);
U.S. Cl.
CPC ...
E21B 21/103 (2013.01); E21B 4/02 (2013.01); E21B 34/08 (2013.01); E21B 2034/007 (2013.01);
Abstract

A device for limiting the flow of drilling fluid through a section of drill string is described. The device includes a cylindrical tube with holes in its periphery. Flow enters the device through an upper end of the tube and a portion of the flow exits through the lower end of the tube. In addition, some of the flow is diverted through the peripheral holes. A valve piston is supported near the lower end of the tube by a spring of approximately constant force through its range of travel. The valve piston moves axially as the flow rate through the tube changes flow rate to ensure that a substantially constant amount of flow exits through the lower end, while the excess flow is diverted from the tube through the peripheral holes. A means of damping or stopping the axial movement of the valve piston is included in the device.


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